The present invention relates to a centrifuge and to a method of operating the centrifuge.
U.S. Pat. No. 5,328,441 shows a centrifuge during whose operation, after the solids are centrifuged from the centrifuged material, the liquid is first drained from the centrifuge basket and subsequently the solids a peeled out of the centrifuge basket by means of a device specifically designed for this purpose. The solids are collected in a manner which is not visible below the centrifuge basket.
If a centrifuge of the above-mentioned type is used in the pharmaceutical field, for example, for obtaining solids from human blood and/or for producing insulin, the problem arises of handling the solids delivered by the centrifuge basket in a manner which is as hygienic and as sterile as possible. Although it is possible to remove the solids xe2x80x9cmanuallyxe2x80x9d from the centrifuge or from a receptacle arranged below the centrifuge, such a handling appears problematic in view of the currently constantly increasing hygiene requirements. Furthermore, there is the problem that, when the discharge of solids is handled manually, losses must be expected which reduces the yield of solids. Specifically when obtaining solids from blood, the interest in obtaining solids from blood with as few losses as possible is particularly high.
German Patent Document DE-U-85 33 545.2 shows a centrifuge of the above-mentioned type. In this centrifuge, solid particles are caught in a bag. German Patent Document DE 35-42 134 A1 also shows a centrifuge of this type.
It is therefore an object of the invention to provide a centrifuge as well as a method of operating the centrifuge by means of which a largely loss-free obtaining of solids from a centrifuged substance such as blood can be implemented while the hygienic standard is raised.
The invention includes a receptacle for catching a portion of the constituents delivered by the centrifuge, particularly the solids. A bag is inserted into the receptacle for receiving the solids from the centrifuge basket. As a result of the catching of the solids in the bag inserted in the receptacle, a largely sterile handling of the solids is permitted because, after the filling or centrifuging operation, the bag, together with its content, must only be removed from the receptacle. Losses of solids when emptying the receptacle are avoided.
A hose connects the interior of the bag with the space surrounding the bag. The hose preferably leads into the interior of the bag in the proximity of the axis of rotation of the centrifuge basket. In the space below the centrifuge basket, because of the friction surfaces of the basket, the air, which surrounds the basket, will also rotate. As a result of the centrifugal forces, this rotation generates a pressure rise from the inside (axis of rotation) to the outside. Since, in addition, the space in the interior areaxe2x80x94thus in the area of the axis of rotationxe2x80x94is connected to the ambient pressure, an excess pressure occurs in the outer area of the interior of the bag. As a result, the bag is xe2x80x9cspread outxe2x80x9d and pressed against the walls surrounding it, so that a particularly uncomplicated filling of the bag is ensured.
The hose preferably leads from the interior of the bag into the space between the bag exterior and the inside wall of the receptacle. When the pressure in the receptacle is lowered during the centrifuging, the pressure gradient generated by the rotation of the basket spreads out the bag. Furthermore, the low pressure facilitates the sterile handling of the centrifuged material.
In another particularly preferred embodiment of the invention, the hose includes a shut-off valve. The valve is closed in order to avoid contact of the solids with the ambient air when pressure in the receptacle increases after a centrifuging operation.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.